The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,h...The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,how MoFim1 is regulated in M.oryzae to precisely rearrange the actin cytoskeleton is unclear.In this study,we found that MoFim1 associates with the M.oryzae mitogen-activated protein(MAP)kinase Pmk1 to regulate actin assembly.MoFim1 directly interacted with Pmk1,and the phosphorylation level of MoFim1 was decreased inΔpmk1,which led to a change in the subcellular distribution of MoFim1 in the hyphae ofΔpmk1.Moreover,the actin cytoskeleton was aberrantly organized at the hyphal tip in theΔpmk1,which was similar to what was observed in theΔmofim1 during hyphal growth.Furthermore,phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94.Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity.Additionally,the expression of the site mutant of MoFim1 S94D(in which serine 94 was replaced with aspartate to mimic phosphorylation)inΔpmk1 could reverse the defects in actin organization and hyphal growth inΔpmk1.It also partially rescues the formation of appressorium failure inΔpmk1.Taken together,these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.展开更多
基金funded by the Natural Science Foundation of Fujian Province,China(2022J01616 and 2023J01483)the Distinguished Young Scientists Fund of Fujian Agriculture and Forestry University of China(xjq202121)+1 种基金the National Natural Science Foundation of China(grant numbers.31970284,31900385)the Fujian Provincial Science and Technology Key Project(2022NZ030014).
文摘The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection.The actin-related protein MoFim1 is a key factor for organizing the M.oryzae actin cytoskeleton.Currently,how MoFim1 is regulated in M.oryzae to precisely rearrange the actin cytoskeleton is unclear.In this study,we found that MoFim1 associates with the M.oryzae mitogen-activated protein(MAP)kinase Pmk1 to regulate actin assembly.MoFim1 directly interacted with Pmk1,and the phosphorylation level of MoFim1 was decreased inΔpmk1,which led to a change in the subcellular distribution of MoFim1 in the hyphae ofΔpmk1.Moreover,the actin cytoskeleton was aberrantly organized at the hyphal tip in theΔpmk1,which was similar to what was observed in theΔmofim1 during hyphal growth.Furthermore,phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94.Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity.Additionally,the expression of the site mutant of MoFim1 S94D(in which serine 94 was replaced with aspartate to mimic phosphorylation)inΔpmk1 could reverse the defects in actin organization and hyphal growth inΔpmk1.It also partially rescues the formation of appressorium failure inΔpmk1.Taken together,these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.
